1. Field of the Invention
The present invention pertains generally to extendable supports and mechanisms for locking the same at arbitrarily extended positions, and is more particularly directed to a lock for a telescoping tubular leg, particularly for use in a tripod of the type used in photographic or cinematographic applications among others.
2. Background of the Invention
Tripod legs typically consist of a number of telescoping tubular sections of successively smaller cross section, each section being slidable within a larger section. Each section, except the smallest, is provided with a lock for locking together each connected pair of tubular sections against telescoping sliding movement so that the support or tripod may be fixed at any desired height within the limits of the extendable support. Existing tripod leg locks typically have included a camming lever mounted to the larger diameter tube section. The lever was pivotable into camming engagement with the inner, smaller diameter tube through an opening in the outer, larger diameter tube. These locks had the effect of applying localized force by the cam lever on one side of the inner tube, which was thus wedged against the opposite inner surface of the larger diameter tube. The locking force is thus applied at diametrically opposed points of the inner tube. If the inner tube is made of thin material, there is a possibility of deforming or flattening the inner tube.